Generally, a turbocharger mounted on a vehicle improves the charging efficiency of intake air that is flowed into combustion chambers of an engine by using the exhaust gas pressure exhausted to an exhaust system of the engine to pressurize the intake air and has been mainly applied to high-power engines.
In addition, the exhaust system of the turbocharger engine is a post-treatment device with high purification that can effectively oxidize not only CO and HC components contained in the exhaust gas, but also SOF components, and has a warming-up catalytic converter (WCC).
Referring to FIG. 1 showing a conventional exhaust system for a turbocharged vehicle, an exhaust connecting pipe 20 bent at 90° with a constant diameter is connected to an outlet of a turbocharger 10 and a catalyst converter 30 (e.g., a warming-up catalyst converter) is mounted at the outlet of the exhaust connecting pipe 20.
Further, an oxygen sensor 40, which senses oxygen in the exhaust gas to be used to determine the degradation state of the catalyst or to determine the rich or lean of the air/fuel ratio (lambda), is inserted into and mounted to the catalyst converter 30.
As shown in FIG. 2, the oxygen sensor 40 is inserted into and fastened to the catalytic converter 30 to prevent the sensing failure due to the condensate accumulation.
Furthermore, the oxygen sensor 40 is inserted between the catalysts in the catalytic converter, not at the turbocharger outlet of a high temperature, to prevent damage due to abrupt temperature rise.
Since the exhaust connecting pipe 20 should be oriented in the direction of the ground, it is provided to be bent at 90° from the turbocharger arranged in the transverse direction. That is, if the exhaust connecting pipe 20 is bent at an angle exceeding 90°, the exhaust performance is deteriorated (e.g., the exhaust gas pressure is increased), so that the exhaust connecting pipe 20 has been applied to be bent at an angle of 90° in order to minimize the exhaust pressure.
However, there was a disadvantage in that only the catalytic converter 30 having a volume defined by the restriction of the space adjacent to the outlet of the exhaust connecting pipe 20 is connected to the outlet of the exhaust connecting pipe 20 when the exhaust connecting pipe 20 is adopted as being bent at 90°.
Furthermore, since the outlet of the exhaust connecting pipe 20 and the catalytic converter 30 are arranged in line toward the ground direction, the space occupied by the exhaust connecting pipe 20 and the catalytic converter 30 is increased in view of the exhaust system component layout, so that the layout of the exhaust system components for a high performance turbo engine of a large size is limited.
In addition, when the exhaust connecting pipe 20 bent at an angle exceeding 90° is adopted, the catalytic converter 30 connected to the outlet of the exhaust connecting pipe 20 is in a diagonal arrangement, which causes the problems that the oxygen sensor 40 cannot be easily inserted straight into the catalytic converter 30 and the sensing performance of the oxygen sensor 40 is degraded because the insertion fastening length of the oxygen sensor 40 for the catalytic converter 30 is not ensured.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.